In a decision watched by officials in 20 states that hold some sex offenders after they complete prison sentences, a federal judge ruled this week that Minnesota's program for such offenders was unconstitutional, reports the New York Times.

Judge Donovan W. Frank of Federal District Court in St. Paul found that the state's program, which holds more than 700 people in two secure facilities for indefinite periods, had failed to release some who no longer met the criteria for being confined.

"The overwhelming evidence at trial established that Minnesota's civil commitment scheme is a punitive system that segregates and indefinitely detains a class of potentially dangerous individuals without the safeguards of the criminal justice system," Judge Frank wrote.

While Judge Frank's ruling, released on Wednesday, does not directly affect civil commitment programs in other states, officials elsewhere were paying close attention to the outcome, largely because questions about the constitutionality, costs and effectiveness of holding sex offenders beyond their prison terms have long been debated.